This invention relates to manometer and CO2 detectors used in patient ventilation systems. More particularly, it refers to a disposable apparatus combining both a manometer and calorimetric CO2 detection device in a patient monitor receiving exhaled air from a patient.
Manometers for measuring air pressure in a patient ventilation system and CO2 detectors for determining the presence of CO2 above the CO2 in ambient air coming from an intubated patient are well known. Ports have to be inserted on the patient ventilation system for both the manometer and CO2 detector. This creates additional work and expenditure of time for the caregiver. It would be desirable to have a single disposable monitor connected to the patient recording both air pressure and the presence of CO2 in exhaled air. No such disposable monitor exists at present.
This invention solves the problem of the prior art by providing a self-contained disposable monitor recording both air pressure and the existence of CO2 in a patient""s exhaled breath in the same instrument. The monitor has two housing components which when joined together have a patient port and an input port. The top housing component contains calorimetric CO2 indicator paper and a shaft with a helical external configuration. A pointer in a top portion of the top housing rotates with the shaft. A clear cover contains indicia for noting air pressure in the monitor as the shaft turns. The bottom housing has a receptacle for a spring that exerts pressure on a membrane above the spring. A pair of baffles and a filter between the baffles contain bores for receipt of a hollow stem directed upwardly from the center of the membrane. The inner wall of the stem has a notch for receipt of the helical configuration on the shaft in the upper housing. As exhaled air flows into the monitor from the patient, the air pressure is indicated by the pointer which turns in response to air pressure on the membrane and the CO2 indicator paper changes color in response to the CO2 level in the exhaled breath coming from the patient.